July 28, 2012
A new study revealed how hand shape can be identified via measurements on 3 hand dimensions, including: finger length, palm width & palm length.
The study points out that each of the so-called ‘elemental hand shapes’ (earth hand shape, fire hand shape, air hand shape, and water hand shape) can be recognized by it’s proportions relative to each other.
The picture above demonstrates how your hand shape can be identified via the ‘hand shape profile’ – which concerns a code with three elements involved, where the combination reveals the (elemental) hand shape type.
More details are discussed in the article:
Finger length proportions & elemental hand shapes!
Last summer professor John T. Manning re-designed his popular 2D:4D digit ratio theory about finger length ratio development in the hand. While he had already mentioned the role of prenatal sex steroids, now the updated theory now focusses on the balance between sexe hormones (androgens) testosterone & oestrogen during the development in the whomb!
Professor Manning presented his revised theory in the PNAS magazine under the title: ‘Resolving the role of prenatal sex steroids in the development of digit ratio‘.
Manning’s new working hypothesis now includes e.g. the following 7 key-elements:
1 – The 2D:4D digit ratio results from the balance between prental androgens testosterone & estrogen;
2 – A high 2D:4D digit ratio results from relatively low testosterone concentrations – OR relatively high estrogen concentrations;
3 – A low 2D:4D digit ratio results from relatively high testosterone concentrations – OR relatively low estrogen concentrations;
4 – The ring finger (= digit 4D) is featured with many more hormone receptors compared to the index finger (- digit 2D), therefore the 2D:4D digit ratio is mostly driven by changes in the length of the ring finger (due to prenatal hormone concentrations);
5 – Studies in human & animals indicate that the link between prenatal androgens and 2D:4D digit ratio is generally stronger for the right hand;
6 – 2D:4D Digit ratio varies with sexe: males generally have longer fourth digits relative to second digits than females;
7 – 2D:4D Digit ratio varies with ethnicity.
A quote from Manning’s article:
“Armed with this list of skeletogenic genes linked to 2D:4D, we can now be more focused in our examination of the links between 2D:4D and the etiology of sexdependent behaviors and diseases of the immune system, cardiovascular disorders, and a number of cancers.”
“Prenatal sex steroids [i.e., prenatal testosterone (PT), prenatal estrogen (PE)] are often implicated in the etiology of behaviors and diseases. They show sex differences (higher concentrations of PT to PE in males), with PT peaking at the end of the ﬁrst trimester, and cause permanent “organizational” changes in the brain and other organ systems. It has een suggested that relative levels of PT and PE may have differential effects on fertility, speed, strength, aggression, autism, many cancers, and heart disease.”
September 6, 2011
Wearing your heart on your sleeve is merely an adage, but most people do display their emotions – even if unintentionally – on their faces. Women tend to be better than men at reading other people’s subtle facial cues, especially cues from the eyes. Because of the gender difference in cognitive empathy – the ability to notice and correctly interpret body language – psychobiologistsscientists that study psychology from a biological perspective, or vice versa have hypothesized that testosterone – a sex hormone present in much higher levels in males versus females levels – could play a role in “mind reading” ability, or lack thereof.
A new study in PNASProceedings of the National Academy of Sciences validates this hypothesis by demonstrating that a dose of testosterone can make women lose some of their cognitive empathy. Researchers recruited 16 young women (age 20-25) to participate in their study. The women were given either a testosterone pill or a placebo, and then tested on their ability to assess emotions based on photographs of eyes. The test the women took is called the Adult Eyes Test, and is available for free from the Autism Research Center at the University of Cambridge. Here’s a sample question (formatting is slightly modified):
For the correct answer, click here.
Each woman was tested twice – once with placebo and once with real testosterone (in random order; they didn’t have any idea which was which). 75% of the women performed worse on the “mind reading” test after taking testosterone than after taking a placebo. So to a first approximation, an artificial increase in testosterone levels impaired women’s abilities to interpret facial expressions.
But the results aren’t quite that simple. Some women were less affected by the extra testosterone than others, and the researchers had a hunch that this could relate to their exposure to testosterone in the womb. All fetuses are exposed to testosterone while developing, but to different extents. There is a simple way to qualitatively measure fetal testosterone exposure – this parameter is believed to be correlated to the adult ratio of ring finger length to index finger length (see picture at the top of this post).
Larger ratios of ring finger to index finger lengths correspond to higher fetal testosterone levels. This study showed no difference between the inherent expression-reading ability of women exposed to higher vs. lower doses of testosterone in the womb. However, the women with longer ring fingers (higher fetal testosterone) seemed to be more easily impaired when given a dose of testosterone in pill form.
Thus, this study demonstrated that (1) testosterone administered to women can impair their ability to read facial expressions, and (2) women who experienced more testosterone in the womb are more sensitive to the effects of testosterone administered as adults. Nothing further can be definitively gathered from these results, but they seem to suggest that men’s testosterone levels could be to blame for their increased confusion about what others (especially women!) are thinking/feeling.
PS. A brand new study reported by researchers from Florida has recently (sep 2011) presented proof that fingers have hormonal receptors!
The following finger length study presents a likewise effect:
How lingerie can sharpen the financial mind!
JULY 4, 2011 – Finally… researchers in Korea think that they found the long awaited proof: finger length can predict penis length! Korean researchers at the In Ho Choi of Gacheon University Gil Hospital, have presented results in a sample of urological patients which indicate that in men with a low ’2D:4D finger ratio‘ more often is featured with a long phallus (compared to men with a high ‘digit ratio’).
The researchers from Korea found that the ratio between the pointer finger & ring figner (2nd and 4th digits) on men’s right hand correlate to the length of his flaccid and stretched phallus (not errected). A lower index-to-ring finger length ratio indicates a longer (stretched) penis.
NOTICE: The table below is taken from the scientific article; it e.g. illustrates that likewise results were found for body length and penis length – for the ‘flaccid condition’ the result for body height were slightly higher than for the 2D:4D digit ratio, but in the ‘stretched condition’ finger length ratio was a better predictor for penis length!
The key to this relationship between penis size & finger length likely lies in the womb, a team member added:
“During the fetal period, high concentrations of testosterone lead to high testicular activity, resulting in a lower digit ratio, in the present study, patients with a lower digit ratio tended to have a longer stretched penile length.”
The researchers also added that the length of the stretched and flaccid penis does show “a strong correlation” with an erect penile length.
The Korean report was published on july 4 in the Asian Journal of Andrology, and the scientific article is available at Nature.com.
NO SURPRIZING RESULTS!
Actually, the Korean results are not surprizing at all. Because British professor John Manning had already pointed out in his second book ‘The Finger Book‘ (2008) that a study in the Naval and Veteran’s Hospital of Athens (Greece, 2002) had pointed out that the length of the index finger correlates with the length, glans & volume of the penis.
Manning commented (in ‘The Finger Book’):
“Spyropoulos and his collegues did not measure the remaining fingers, so we cannot be sure of their relationship to penis length. My guess is that they would have found the ring finger the strongest predictor, and that long ring fingers in relation to index fingers would be associated with longer penises.”
So, the 2011 Korean study shows ‘finger professor’ John Manning was right… again!
MORE ABOUT THE SCIENCE OF FINGERS:
48 Reports about the 2D:4D finger length ratio!
June 25, 2011
As a research scientist, Dr. Erina Lee is responsible for the international relationships research at eHarmony. In the following article she described how to use hands in building relationships!
Whether they’re soft and manicured, strong and calloused, weathered and wrinkled—hands come in all shapes and sizes and can often say a lot about you. They can reveal the tattered fingernails of nervous nail biter, the orange fingers of a cheese puff lover, or the worn hands of a grandmother. And when you look even closer at the many lines and wrinkles, is it possible that your hands can reveal even more? Some people believe that clues to our basic selves can be found in the details of our hands. But do our hands really tell us anything of importance about who we really are? Is it possible that the numerous bumps and ridges unique to every hand hold some insight into our level of intelligence or into our love lives?
In an eternal quest for self-discovery, people have looked towards hand readers, among other mystics, to see if the lines in their hands really tell them something meaningful about themselves and their future. In current times, people turn to internet quizzes and online hand reading to make sense of the heart and life lines and the shape of their hands. Although these tests and quizes can be fun, when put to the test of empirical science, most of these claims and predictions cannot be verified. Furthermore, these uncorroborated predictions about personality traits and future events leave palm reading in the category of a pseudoscience.
Despite the inaccuracy of palmistry readings, however, there are aspects of the hands that have been studied empirically, including finger length. When looking at the palm of your hand, fingers straight together, you will likely notice a difference between your second (index) and fourth (ring) fingers. On average women have longer index fingers, compared to ring fingers while men have longer ring fingers compared to index fingers. This association between the two fingers, called the 2D:4D ratio, is related to levels of androgen exposure (a sex hormone higher in men) in the womb. That means that the amount of male hormones a fetus is exposed to determines this very specific detail of finger length in the hands. The precise mechanism by which androgen works is not entirely clear, but in general most theorists believe that increasing androgen exposure will masculinize a fetus. There is also some evidence suggesting that either too much or too little androgen can be feminizing to the fetus.
Because androgen exposure is related to sexual development and masculinization, researchers have begun to wonder if the 2D:4D ratio, as a marker of hormone exposure, may also predict other characteristics. Hormone exposure has been linked to things like general physical health, cognitive abilities, personality, job preferences, attractiveness, and sexual orientation. While the 2D:4D ratio may relate to these developmental characteristics, thus far the evidence supporting such a link is at best described as mixed. For example, there has been much attention dedicated to whether the 2D:4D ratio relates to sexual orientation. While there have been several studies in this area, some have shown no differences between heterosexual and homosexual men in their 2D:4D ratios (e.g., Williams et al., 2000), and others, like Lippa, have shown heterosexual men having lower 2D:4D ratios compared to homosexual men. Similarly with other characteristics like personality and attraction, the research findings have been fairly inconsistent.
Another aspect of the hands that have been conclusively studied are the ridges, the ones that cover the palms and fingers, the ones that make up our unique fingerprints. The study of these ridges is called dermatoglyphics. Similar to the finger length, these ridges are known to be established earlier in the embryonic development, while the fetus is still in the womb. Researchers have shown dermatoglyphic differences between non-deficient people and those with cognitive or genetic abnormalities, like schizophrenia, Down’s syndrome, and intellectual disability. For example, individuals diagnosed with schizophrenia show fewer ridges between two specific points under the second and third fingers [a-b ridge count] compared to non-schizophrenic controls (Bramon et al., 2005). These findings support the idea that changes in the prenatal environment can display its effects in multiple ways, including changes in cognitive development and ridges of the hands. However, the findings do not assume that all people with fewer ridges have cognitive deficiencies.
To summarize, we do know that specific details in our hands are affected by early hormonal exposure and other environmental influences in the womb. And we know that this early exposure also affects other aspects of our development. While it is intriguing to speculate further that details in our hands can predict aspects of our personality or behavior, these conjectures have not been empirically supported. It’s also likely that there are more direct measures of personality, intelligence, and behavioral traits rather than the hands. But even though you can’t currently rely on your hands to unlock all of your mysteries, one thing you can count on is more studies and discussion about them to come.
The video ‘Evolution of the human hand’ - presents a detailed picture of how modern science perceives the evolution of the human hand in time. The video is sort of based on Darwin’s evolution theory, but the details were delevered by experts in anthropology who studied how the hand shape, finger length & palmar creases evolved during the past 1.8 million years.
The video demonstrates how the ‘early’ humanoid hands (and primates) are typically featured with 3 or more ‘complete transverse creases’ (multiple simian lines), which are positioned horizontal in the hand + two major vertical lines. While at the end of the video displays a typical human hand featured with only 2 curved, oblique positioned ‘primary palmar creases’ (heart line and head line) + one major vertical line (life line).
And the differences between the human hand and the hands of primates served as a model for the evolution of the human hand in time - see below the hands of a man compared to the hands of a baboon, orangutang & chimpanzee.
Another important figure in the history of medical science was the Scottish surgeon John Hunter, who turned the attention of science from the structure of hands to it’s function:
“Structure is the intimate expression of function”
- John Hunter, Scottish surgeon (1728-1793) -
More details about the evolution of other features of the human hand are presented in the articles:
December 29, 2010
Earlier this month, British researchers published new research presenting a link between the relative length of the index finger and the risk of developing prostate cancer. In men with an index finger longer than the ring finger the chances are 33% higher for not developing the disease.
Often such studies are qualified by non-experts as “nonsense” – initially because of the association with classical palmistry. Usually a main argument of concern is the seize of the studied sample: many ’2D:4D digit ratio’ studies have been focused relatively small samples, and usually with the statistics were simly not strong enough to be applied to individuals. But those arguments can not be used to the describe the new British study!
The new British research involves a study where the hands of 1,524 prostate cancer patients were examined, which were compared with a control group of 3,044 men.
It can also be noted that Professor John Manning described in his second book ‘The Finger Book‘ with great details the suspected link between the ’2D:4D digit ratio’ and prostate cancer – a complex theory about of role glutamine chains in the sensitivity of hormone receptors, which in their turn play a role in the activation of testosterone in the body:
“…The various forms of the androgen receptor have important consequences for our health and behaviour. For example, African-American men have shorter glutamine chains (high sensitivity to testosterone) than white men. Short glutamine chains are associated with an increased susceptibility to prostate cancer, and this may in part explain why the incidence of prostate cancer is higher in African-Americans than in white Americans. …”
In short, there seems to exist a triangular relationship between: 1) the high percentage of prostate cancer in Americans with African ancestry, 2) the length of the glutamine chains, and 3) the length ratio between index finger and ring finger.
The importance of the new British study can be recognized in the fact the use of preventive screening for prostate cancer – which is anno 2010 usually done through the use of a blood test – is still an object of confusion. Simply because the benefits of the screening devices are still very unclear. Meanwhile it is a fact that prostate cancer is known as the No. 1 cause of death from cancer in men (see picture below).
The British researchers therefore are speculating about how to add a practical application of their finger length study to the traditional methods of prostate cancer prevention screening!
December 12, 2010
Since Winston Churchill’s use of the ’V-sign’ in 1941, this gesture is generally recognized as a sign for ‘victory’. But outside the UK, Ireland, New Zealand and Australia few people are aware of the insulting version of almost the same gesture: a ‘v-sign with the palm inwards’, which is often recognized as an alternative for ‘the finger’. Earlier this month British scientists found that finger length is involved in the severity of the insulting version of the V-gesture.
Scientists at the recent FIFA meeting that awarded the 2018 World Cup to Russia have discovered that people with long middle fingers are capable of increasing the severity of the traditional two-fingered ‘V gesture – with the palm inwards’.
‘Prince William’s gesture was noticeably more aggressive than that of David Cameron, who has a relatively short middle finger,’ said Professor Thomas Boycott from Cambridge. ’The Prince’s gesture was a clear ‘Fuck you, you lying twat with knobs on’, whilst Cameron’s was more ‘Up yours, you stupid tosser’.’
V-signs have been given throughout history, with long-fingered people performing best. Short-fingered Winston Churchill’s gesture when telling journalists to stop taking photographs was incorrectly taken as a ’V for Victory’.
‘Then again,’ added Boycott, ‘what about that short-fingered man who swerved to avoid me this morning and merely gestured to indicate I should eat a hot dog with plenty of ketchup on it? Most peculiar, in the circumstances.’
Researchers presented earlier today new evidence that neanderthals were more competitive & promiscuous than we are today! Maybe more surprizing is the method which the researchers used to acquire their new findings: via finger length measurements!
The study, published in the Proceedings of the Royal Society B, draws upon a famous and controversial indicator of social behavior: the comparative length of the index finger and the ring finger, also known as the 2D:4D finger ratio. If the ring finger is longer than the index finger, that’s supposed to be correlated with higher prenatal exposure to androgens — resulting in a higher proclivity for aggressiveness and promiscuity.
Scientists, in collaboration with researchers at the universities of Southampton and Calgary, used finger ratios from fossilised skeletal remains of early apes and extinct hominins, as indicators of the levels of exposure species had to prenatal androgens – a group of hormones that is important in the development of masculine characteristics such as aggression and promiscuity.
It is thought that androgens, such as testosterone, affect finger length during development in the womb. High levels of the hormones increase the length of the fourth finger in comparison to the second finger, resulting in a low index to ring finger ratio (2D:4D digit ratio). Researchers analysed the fossil finger bone ratios of Neanderthals and early apes, as well as hominins, Ardipithecus ramidus and Australopithecus afarensis, to further understanding of their social behaviour.
The team found that the fossil finger ratios of Neanderthals, and early members of the human species, were lower than most living humans, which suggests that they had been exposed to high levels of prenatal androgens. This indicates that early humans were likely to be more competitive and promiscuous than people today.
The results also suggest that early hominin, Australopithecus – dating from approximately three to four million years ago – was likely to be monogamous, whereas the earlier Ardipithecus appears to have been highly promiscuous and more similar to living great apes. The research suggests that more fossils are needed to fully understand the social behaviour of these two groups.
Dr Susanne Shultz, from the Institute of Cognitive and Evolutionary Anthropology at the University of Oxford describes:
“Social behaviours are notoriously difficult to identify in the fossil record. Developing novel approaches, such as finger ratios, can help inform the current debate surrounding the social systems of the earliest human ancestors.”
And Dr Emma Nelson, an archaeologist from the University of Liverpool, argues that comparing the finger-length ratios of extinct and present-day species is a valid technique for making an indirect assessment of our long-gone ancestors’ social behavior. She said:
“It is believed that prenatal androgens (male sex hormones) affect the genes responsible for the development of the fingers, toes and the reproductive system. We have recently shown that promiscuous primate species have low index to ring finger ratios, while monogamous species have high ratios.”
“We used this information to estimate the social behaviour of extinct apes and hominins. Although the fossil record is limited for this period, and more fossils are needed to confirm our findings, this method could prove to be an exciting new way of understanding how our social behaviour has evolved.